Example of an user selected page_size in flask-admin

gistfile1.py

from flask import Flask, session, request
from flask_sqlalchemy import SQLAlchemy

import flask_admin as admin
from flask_admin.contrib import sqla
from flask_admin import expose

# Create application
app = Flask(__name__)

# Create dummy secrey key so we can use sessions
app.config['SECRET_KEY'] = '123456790'

# Create in-memory database
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///sample_db_3.sqlite'
app.config['SQLALCHEMY_ECHO'] = True
db = SQLAlchemy(app)


# Flask views
@app.route('/', methods=['GET', 'POST'])
def index():
    if request.method == 'POST':
        session['pagesize'] = int(request.form['pagesize'])
    return '''
        <a href="/admin/">Click me to get to Admin!</a>
        <form action="" method="post">
            <p><input type=text name=pagesize>
            <p><input type=submit value=submit>
        </form>
    '''


class Car(db.Model):
    __tablename__ = 'cars'
    id = db.Column(db.Integer(), primary_key=True)
    desc = db.Column(db.String())

    def __unicode__(self):
        return self.desc


class CarAdmin(sqla.ModelView):
    column_display_pk = True

    @expose('/')
    def index_view(self):
        """
            List view
        """
        if self.column_editable_list:
            form = self.list_form()
        else:
            form = None

        if self.can_delete:
            delete_form = self.delete_form()
        else:
            delete_form = None

        # Grab parameters from URL
        view_args = self._get_list_extra_args()

        # Map column index to column name
        sort_column = self._get_column_by_idx(view_args.sort)
        if sort_column is not None:
            sort_column = sort_column[0]

        # Get count and data
        count, data = self.get_list(view_args.page, sort_column, view_args.sort_desc,
                                    view_args.search, view_args.filters,
                                    page_size=session.get('pagesize', 20))

        # Calculate number of pages
        if count is not None:
            num_pages = count // session.get('pagesize', 20)
            if count % session.get('pagesize', 20) != 0:
                num_pages += 1
        else:
            num_pages = None

        # Various URL generation helpers
        def pager_url(p):
            # Do not add page number if it is first page
            if p == 0:
                p = None

            return self._get_list_url(view_args.clone(page=p))

        def sort_url(column, invert=False):
            desc = None

            if invert and not view_args.sort_desc:
                desc = 1

            return self._get_list_url(view_args.clone(sort=column, sort_desc=desc))

        # Actions
        actions, actions_confirmation = self.get_actions_list()

        clear_search_url = self._get_list_url(view_args.clone(page=0,
                                                              sort=view_args.sort,
                                                              sort_desc=view_args.sort_desc,
                                                              search=None,
                                                              filters=None))

        return self.render(
            self.list_template,
            data=data,
            form=form,
            delete_form=delete_form,

            # List
            list_columns=self._list_columns,
            sortable_columns=self._sortable_columns,
            editable_columns=self.column_editable_list,

            # Pagination
            count=count,
            pager_url=pager_url,
            num_pages=num_pages,
            page=view_args.page,
            page_size=self.page_size,

            # Sorting
            sort_column=view_args.sort,
            sort_desc=view_args.sort_desc,
            sort_url=sort_url,

            # Search
            search_supported=self._search_supported,
            clear_search_url=clear_search_url,
            search=view_args.search,

            # Filters
            filters=self._filters,
            filter_groups=self._get_filter_groups(),
            active_filters=view_args.filters,

            # Actions
            actions=actions,
            actions_confirmation=actions_confirmation,

            # Misc
            enumerate=enumerate,
            get_pk_value=self.get_pk_value,
            get_value=self.get_list_value,
            return_url=self._get_list_url(view_args),
        )


# Create admin
admin = admin.Admin(app, name='Example: SQLAlchemy2', template_mode='bootstrap3')
admin.add_view(CarAdmin(Car, db.session))

if __name__ == '__main__':

    # Create DB
    db.drop_all()
    db.create_all()

    for x in xrange(1, 51):
        db.session.add(Car(desc='car1'))
    db.session.commit()

    # Start app
    app.run(debug=True)